An important feature of the TDD (Time Division Duplex) system is that the subframe for uplink and downlink transmission is configurable. The frame structure of the TDD system of the current LTE (Long Term Evolution) is shown in FIG. 1. A radio frame of 10 ms is divided into two half frames of 5 ms, and each half frame of 5 ms further comprises 8 normal time slots and 3 special time slots: a downlink time slot DwPTS, an uplink and downlink protection time slot GP, and an uplink time slot UpPTS. The sum of the durations of the three special time slots is 1 ms, and they constitute one subframe of 1 ms; each two continuous normal time slots constitute one subframe of 1 ms. In one radio frame of 10 ms, the former half frame of 5 ms comprises 4 subframes constituted by the normal time slots, being respectively subframe #0, subframe #2, subframe #3 and subframe #4, and one subframe constituted by the three special time slots; the latter half frame of 5 ms also comprises 4 subframes constituted by the normal time slots, being respectively subframe #5, subframe #6, subframe #7 and subframe #8, and one subframe constituted by the three special time slots (not shown in the Figure). Wherein, subframe #0, subframe #5 and the DwPTS are fixed as downlink time slots.
In the above frame structure, the proportion of the uplink and the downlink subframes (which refer to the subframes constituted by the normal time slots of uplink and downlink, excluding the subframes constituted by the special time slots) is related to a switching period. When the switching period is 5 ms, there are three options of the proportion of the uplink and downlink subframes: 3:1, 2:2 and 1:3. When the switching period is 10 ms, since subframe #5 and the DwPTS are fixed as the downlink subframes, there are also four options of the proportion of the uplink and downlink subframes: 3:6/2:7/1:8 and 5:3. Wherein, a further discussion is still to be conducted for the situation when the proportion of the uplink and downlink subframes is 3:5 in the period of 5 ms and the proportion of the uplink and downlink subframes is 10:0 in the period of 10 ms.
A resource indication signaling assigned to uplink data is transmitted via a downlink control channel, and this requires to establish a corresponding relationship between the uplink subframes and the downlink subframes, and then users can determine the uplink subframe on which the transmission should be performed after obtaining the resource indication signaling of the uplink data from the control channel of the downlink subframes.
Currently, it is regulated in the LTE systems that users transmit data at a corresponding location according to the indication of the uplink resource indication signaling in the (n+4)th uplink subframe after receiving the uplink resource indication signaling in the nth downlink subframe. In the FDD (Frequency Division Duplex) system, the uplink subframes and the downlink subframes are equal to each other in number, and a one-to-one corresponding relationship can be established between the uplink subframes and the downlink subframes according to this rule.
However, in the TDD system implementation process, there is at least the following problem in the prior art:
In the TDD system, when the number of the uplink subframes is larger than that of the downlink subframes, the uplink resource indication signals of multiple uplink subframes will be transmitted in one downlink subframe. If the original solution is followed, users of different uplink subframes will transmit data at the same resource of the same uplink subframe, which will result in mutual interference therebetween and affect system performance.